Vehicles such as cars, vans, trucks and buses can be constructed on a supporting structure known as a frame, chassis or underbody. In a body-on-frame design, the frame is separate from the body of the vehicle and components of the vehicle such as the engine, drivetrain and body are coupled to the frame. In contrast, the body and frame are at least partially integrated with one another in uni-body construction. The frame can comprise a plurality of rails, beams, tubes and other structural members coupled together to form a load bearing structure.